-
European Journal of Ophthalmology 2016To evaluate the effects of intravitreal autologous plasmin injection (IVAP) on vitreoretinal diseases and vitreolysis.
PURPOSE
To evaluate the effects of intravitreal autologous plasmin injection (IVAP) on vitreoretinal diseases and vitreolysis.
METHODS
In this interventional, prospective, case series pilot study, 8 eyes were assigned to IVAP. Plasminogen as centrifuged from the patients' plasma was converted to plasmin by adding urokinase. A total of 0.2 mL extracted plasmin was injected intravitreally. Posterior vitreous detachment (PVD) and potential injection-related complications at week 4 were the primary outcome measures. Secondary outcomes included changes in best-corrected visual acuity (VA) (logMAR) and central macular thickness (CMT).
RESULTS
Mean age of the patients was 54.35 years. Two patients had complete PVD and 3 patients had partial PVD. Four patients had decrease in CMT. The VA was not changed in 6 patients, improved in 1 patient, and decreased in 1 patient. No uveitis, endophthalmitis, or postinjection vitreous hemorrhage was observed.
CONCLUSIONS
This pilot study demonstrated the efficacy of urokinase-prepared IVAP injection on releasing vitreomacular traction and inducing vitreolysis.
Topics: Aged; Female; Fibrinolysin; Fibrinolytic Agents; Humans; Intravitreal Injections; Male; Middle Aged; Pilot Projects; Prospective Studies; Tomography, Optical Coherence; Urokinase-Type Plasminogen Activator; Visual Acuity; Vitreous Body; Vitreous Detachment
PubMed: 26044374
DOI: 10.5301/ejo.5000628 -
Biochemistry Oct 2011Perioperative bleeding is a cause of major blood loss and is associated with increased rates of postoperative morbidity and mortality. To combat this, antifibrinolytic...
Perioperative bleeding is a cause of major blood loss and is associated with increased rates of postoperative morbidity and mortality. To combat this, antifibrinolytic inhibitors of the serine protease plasmin are commonly used to reduce bleeding during surgery. The most effective and previously widely used of these is the broad range serine protease inhibitor aprotinin. However, adverse clinical outcomes have led to use of alternative serine lysine analogues to inhibit plasmin. These compounds suffer from low selectivity and binding affinity. Consequently, a concerted effort to discover potent and selective plasmin inhibitors has developed. This study used a noncombinatorial peptide library to define plasmin's extended substrate specificity and guide the design of potent transition state analogue inhibitors. The various substrate binding sites of plasmin were found to exhibit a higher degree of cooperativity than had previously been appreciated. Peptide sequences capitalizing on these features produced high-affinity inhibitors of plasmin. The most potent of these, Lys-Met(sulfone)-Tyr-Arg-H [KM(O(2))YR-H], inhibited plasmin with a K(i) of 3.1 nM while maintaining 25-fold selectivity over plasma kallikrein. Furthermore, 125 nM (0.16 μg/mL) KM(O(2))YR-H attenuated fibrinolysis in vitro with an efficacy similar to that of 15 nM (0.20 μg/mL) aprotinin. To date, this is the most potent peptide inhibitor of plasmin that exhibits selectivity against plasma kallikrein, making this compound an attractive candidate for further therapeutic development.
Topics: Antifibrinolytic Agents; Aprotinin; Binding Sites; Drug Design; Fibrinolysin; Humans; Kinetics; Oligopeptides
PubMed: 21877690
DOI: 10.1021/bi201203y -
The American Journal of Physiology Feb 1993Treatment of cultured bovine carotid artery endothelial cells with 10(-7) M plasmin increased arachidonate release coupled with the increase in prostacyclin production....
Treatment of cultured bovine carotid artery endothelial cells with 10(-7) M plasmin increased arachidonate release coupled with the increase in prostacyclin production. The stimulatory effect of plasmin on arachidonate release could be divided into the early and late phases according to its calcium dependency and pertussis toxin sensitivity. The early phase of plasmin-induced arachidonate release was a calcium-dependent and pertussis toxin-sensitive response, which was observed within 20 min after plasmin treatment. The late phase was a calcium-independent and pertussis toxin-insensitive response, which was induced gradually from 20 to 60 min. Induction of the early phase of plasmin's effect required both the lysine binding and catalytic sites in plasmin molecule because it was inhibited either by the binding antagonist tranexamic acid or by the serine protease inhibitor aprotinin. Guanosine 5'-O-(2-thiotriphosphate) potentiated the effect of plasmin in permeabilized or nonpermeabilized cells, indicating that the early phase effect was mediated by a pertussis toxin-sensitive guanosine 5'-triphosphate (GTP)-binding protein. The late phase of plasmin's effect was due to the catalytic activity because it was inhibited by aprotinin but not by tranexamic acid. Microplasmin structurally having the catalytic sites induced a similar late phase effect. Plasmin did not elicit the metabolism of phosphatidyl polyphosphoinositides. These studies demonstrate that the activation of phospholipase A2, which results in arachidonate release, in the early phase of plasmin's effect is a receptor-mediation via GTP-binding protein that is not coupled through phospholipase C activation.
Topics: Animals; Arachidonic Acid; Calcium Channel Blockers; Catalysis; Cattle; Cells, Cultured; Cholera Toxin; Endothelium, Vascular; Epoprostenol; Fibrinolysin; GTP-Binding Proteins; Humans; Lysine; Pertussis Toxin; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Receptors, Cell Surface; Virulence Factors, Bordetella
PubMed: 8383426
DOI: 10.1152/ajpcell.1993.264.2.C271 -
Clinica Chimica Acta; International... Oct 1975
Topics: Fibrinolysin; Humans; Immunoelectrophoresis; Isoenzymes
PubMed: 126825
DOI: 10.1016/0009-8981(75)90149-7 -
The Journal of Biological Chemistry Mar 1991Actin, one of the most abundant cellular proteins, circulates at micromolar concentrations in peripheral blood. Because actin released from dying cells may be trapped in...
Actin, one of the most abundant cellular proteins, circulates at micromolar concentrations in peripheral blood. Because actin released from dying cells may be trapped in fibrin clots that form at sites of tissue injury, we examined the effects of actin upon lysis of fibrin clots in vitro. Incorporation of native rabbit skeletal muscle actin into fibrin clots slowed their rates of lysis for periods of up to 24 h, an effect not seen when comparable concentrations of human IgG or bovine serum albumin were added instead. Actins isolated from a variety of sources inhibited plasmin's hydrolysis of the synthetic substrate S-2251 in a noncompetitive manner, with a Ki of a 0.6-3.1 microM. Inhibition was rapid, but covalent actin-plasmin complexes were not formed. Both epsilon-aminocaproic acid and tranexamic acid prevented actin's inhibition of plasmin, suggesting that accessible lysine residues of actin interact with the kringle (lysine-binding) regions of plasmin. Neither of the high-affinity actin-binding proteins of plasma (plasma gelsolin and vitamin D-binding protein) prevented actin from inhibiting plasmin. These findings suggest that actin released into the extracellular space following cell death may modulate plasmin action, and hence a number of plasmin-dependent biological responses, at sites of inflammation and tissue injury.
Topics: Actins; Animals; Binding Sites; Binding, Competitive; Blood Platelets; Calcium-Binding Proteins; Electrophoresis, Polyacrylamide Gel; Fibrinolysin; Gelsolin; Humans; Hydrolysis; Kinetics; Microfilament Proteins; Rabbits; Vitamin D-Binding Protein
PubMed: 1848244
DOI: No ID Found -
The Journal of Biological Chemistry Jul 2001Serine proteases are implicated in a variety of processes during neurogenesis, including cell migration, axon outgrowth, and synapse elimination. Tissue-type plasminogen...
Serine proteases are implicated in a variety of processes during neurogenesis, including cell migration, axon outgrowth, and synapse elimination. Tissue-type plasminogen activator and urokinase-type activator are expressed in the floor plate during embryonic development. F-spondin, a gene also expressed in the floor plate, encodes a secreted, extracellular matrix-attached protein that promotes outgrowth of commissural axons and inhibits outgrowth of motor axons. F-spondin is processed in vivo to yield an amino half protein that contains regions of homology to reelin and mindin, and a carboxyl half protein that contains either six or four thrombospondin type I repeats (TSRs). We have tested F-spondin to see whether it is subjected to processing by plasmin and to determine whether the processing modulates its biological activity. Plasmin cleaves F-spondin at its carboxyl terminus. By using nested deletion proteins and mutating potential plasmin cleavage sites, we have identified two cleavage sites, the first between the fifth and sixth TSRs, and the second at the fifth TSR. Analysis of the extracellular matrix (ECM) attachment properties of the TSRs revealed that the fifth and sixth TSRs bind to the ECM, but repeats 1-4 do not. Structural functional experiments revealed that two basic motives are required to elicit binding of TSR module to the ECM. We demonstrate further that plasmin releases the ECM-bound F-spondin protein.
Topics: Amino Acid Sequence; Binding Sites; Cell Division; Cell Line; Cell Movement; DNA; Dose-Response Relationship, Drug; Extracellular Matrix; Extracellular Matrix Proteins; Fibrinolysin; Gene Deletion; Growth Substances; Humans; Molecular Sequence Data; Mutation; Neural Cell Adhesion Molecules; Peptides; Plasmids; Protein Binding; Protein Structure, Tertiary; Reelin Protein; Sequence Homology, Amino Acid; Structure-Activity Relationship; Tissue Plasminogen Activator; Transfection
PubMed: 11359777
DOI: 10.1074/jbc.M102585200 -
Cancer Research Nov 2005Plasmin is shown to play a crucial role in many pathophysiologic processes primarily through its ability to degrade extracellular matrix (ECM) and/or mobilizing growth...
Plasmin is shown to play a crucial role in many pathophysiologic processes primarily through its ability to degrade extracellular matrix (ECM) and/or mobilizing growth factors that are sequestered in the ECM. Cysteine-rich 61 (CCN1) is a matricellular protein of which expression is up-regulated in cancer and various vascular diseases. The present study was undertaken to investigate whether plasmin liberates CCN1 from the ECM and whether the released growth factor modulates endothelial cell migration. Treatment of breast carcinoma cells (MDA-MB-231) with plasmin released a truncated form of CCN1 (28 kDa) into the overlying medium. Experiments with recombinant CCN1 confirmed that plasmin effectively cleaves CCN1. Thrombin and other clotting/fibrinolytic proteases are ineffective in cleaving CCN1. Further studies revealed that the conditioned medium of plasmin-treated carcinoma cells supports endothelial cell migration and that antibodies specific to CCN1 blocked this enhancing effect. These data were the first to show that plasmin can liberate a pluripotent matrix signaling protein, CCN1, from the ECM. Because both CCN1 and the components of the plasmin generation system are present in tumor cells and a variety of other cells, the proteolysis of CCN1 by plasmin may play a role in many pathophysiologic processes, including tumor cell-mediated angiogenesis.
Topics: Breast Neoplasms; Cell Line, Tumor; Cell Movement; Cysteine-Rich Protein 61; Endothelial Cells; Fibrinolysin; Humans; Immediate-Early Proteins; Intercellular Signaling Peptides and Proteins
PubMed: 16266990
DOI: 10.1158/0008-5472.CAN-05-0982 -
Clinica Chimica Acta; International... Feb 1996Plasmin is a serine protease with trypsin-like specificity and is activated from plasminogen by several plasminogen activators. Since plasmin has lysine binding site in...
Plasmin is a serine protease with trypsin-like specificity and is activated from plasminogen by several plasminogen activators. Since plasmin has lysine binding site in its heavy chain, lysine derivatives react with plasmin and then modify its activity. The effects of lysine derivatives such as epsilon-aminocaproic acid (EACA) and tranexamic acid on bovine plasmin activity were investigated. In the absence of lysine derivatives, the bovine plasmin activity which was evaluated as the amidolytic activity was reduced in a time- or temperature-dependent manner. However, the bovine plasmin activity became stable upon adding EACA or tranexamic acid. When plasmin was incubated at 4 degrees C for 1, 3 or 5 days without lysine derivatives, the plasmin activity decreased to 43.9%, 19.9% and 11.9% of the initial activity, respectively. On the other hand, when plasmin was incubated at 37 degrees C for 1, 3 or 5 days with tranexamic acid, its activity remained at 110%, 95.6% and 85.9%, respectively. After bovine plasmin had been incubated for 5 days at 4 degrees C in the absence of tranexamic acid, the plasmin activity declined to less than 20%. However, when bovine plasmin had been incubated for 5 days at 37 degrees C in the presence of tranexamic acid, the residual plasmin activity was more than 80%. A similar effect of EACA on bovine plasmin was observed, but it was weaker than that of tranexamic acid. Reversed-phase HPLC followed by SDS-PAGE demonstrated that bovine plasmin was degraded into several fragments. Amino acid sequencing of these fragments revealed that the Lys77-Arg78 or Arg78-Ile79, Arg342-Met343 and Arg557-Ile558 peptide bonds in the bovine plasmin molecule were cleft, respectively. Only the fragment consisting of the amino acid region from Met343 to the C-terminal amino acid, Asn786, exhibited amidolytic activity. In proportion to inactivation of the bovine plasmin, this fragment disappeared. The above findings suggest that lysine derivatives react with bovine plasmin and then stabilize the activity of plasmin by preventing the degradation of active fragment (Met343-Asn786).
Topics: Amino Acid Sequence; Aminocaproic Acid; Animals; Cattle; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Enzyme Stability; Fibrinolysin; Hydrolysis; Molecular Sequence Data; Tranexamic Acid
PubMed: 8646816
DOI: 10.1016/0009-8981(95)06183-5 -
Colloids and Surfaces. B, Biointerfaces Dec 2015Components of many vascular prostheses including endovascular stents, heart valves and ventricular assist devices are made using metal alloys. In these blood contacting...
Components of many vascular prostheses including endovascular stents, heart valves and ventricular assist devices are made using metal alloys. In these blood contacting applications, metallic devices promote blood clotting, which is managed clinically by profound platelet suppression and/or anticoagulation. Here it is proposed that the localized immobilization of bioactive plasmin, a critical mediator of blood clot stability, may attenuate metallic prosthesis-induced thrombus formation. Previously described approaches to covalently immobilize biomolecules on implantable materials have relied on complex chemical linker chemistry, increasing the possibility of toxic side effects and reducing bioactivity. We utilize a plasma deposited thin film platform to covalently immobilize biologically active plasmin on stainless steel substrates, including stents. A range of in vitro whole blood assays demonstrate striking reductions in thrombus formation. This approach has profound potential to improve the efficacy of a wide range of metallic vascular implants.
Topics: Fibrinolysin; Humans; Male; Surface Properties; Thrombosis
PubMed: 26551872
DOI: 10.1016/j.colsurfb.2015.10.035 -
Thrombosis Research Sep 2001Thrombolytic drugs do not only stimulate the plasmin system but also induce thrombin activation additionally to the preexisting hypercoagulative state in patients with... (Review)
Review
Thrombolytic drugs do not only stimulate the plasmin system but also induce thrombin activation additionally to the preexisting hypercoagulative state in patients with acute myocardial infarction. Testing the in vitro-derived hypothesis of a plasmin-mediated activation of the contact phase of the coagulation leading to the procoagulant effect, several thrombolytic regimen have been evaluated. Paradoxical thrombin activation (referred to as "thrombolytic paradox") was related to absence of fibrin specificity. Highly fibrin-specific drugs like tenecteplase did not cause additional thrombin activation, while non-fibrin-specific drugs like streptokinase caused a marked additional activation of the contact phase and of thrombin. It could be shown that the thrombolytic paradox was related to the extent of systemic plasmin activation confirming the hypothesis of a plasmin-mediated factor XII/kallikrein system activation as cause of the thrombolytic paradox.
Topics: Fibrinolysin; Fibrinolytic Agents; Humans; Thrombin; Thrombolytic Therapy
PubMed: 11567669
DOI: 10.1016/s0049-3848(01)00297-3